#3 HFSC: rt traffic far more delayed than ls traffic

[amuza]

Hello Russell,

I am testing HFSC in a virtual lab at home. I have Ostinato packet generator sending continuous flows to a host, I have a GNU+Linux machine in between, where I have configured HFSC. Everything is shaped perfectly by HFSC, but there is a problem with delay. I would like to know what I am doing wrong because traffic on the class where I configured rt has more than double delay than any other traffic. In order to check delay I use qperf and ping on the top of the Ostinato flows.

I would be very happy if you could let me know whether you see something wrong in my configuration.

me@gnulinux# tc qdisc show dev eth0
qdisc hfsc 1: root refcnt 2 default 15 
qdisc sfq fa: parent 1:a limit 127p quantum 1514b depth 127 divisor 1024 perturb 10sec 
qdisc sfq f15: parent 1:15 limit 127p quantum 1514b depth 127 divisor 1024 perturb 10sec 
qdisc sfq f1: parent 1:1 limit 127p quantum 1514b depth 127 divisor 1024 perturb 10sec 
qdisc sfq f14: parent 1:14 limit 127p quantum 1514b depth 127 divisor 1024 perturb 10sec 

me@gnulinux# tc class show dev eth0
class hfsc 1: root 
class hfsc 1:1 parent 1: sc m1 0bit d 0us m2 1500Kbit ul m1 0bit d 0us m2 1500Kbit 
class hfsc 1:a parent 1:1 leaf fa: rt m1 250Kbit d 8.0ms m2 100Kbit 
class hfsc 1:15 parent 1:1 leaf f15: ls m1 0bit d 0us m2 150Kbit 
class hfsc 1:14 parent 1:1 leaf f14: ls m1 0bit d 0us m2 150Kbit ul m1 0bit d 0us m2 300Kbit 
class sfq fa:2e2 parent fa: 
class sfq f15:232 parent f15: 
class sfq f15:2c8 parent f15: 
class sfq f14:320 parent f14: 

By the way, I am not sure if it is ok to ask here this kind of questions. Please let me know if you think I should address my HFSC support questions somewhere else, this is the only place I found...

Thank you very much!

[amuza]

I think I can ask it in an easier way.

With the configuration below I get far more delay on 192.168.10.0/24 traffic than on 192.168.20.0/24 traffic.

Am I doing something wrong?

If you think it is better to ask for support somewhere else and you know where, I'd be grateful if you let me know.

Thank you.

tc qdisc add dev eth0 root handle 1: hfsc default 90
tc class add dev eth0 parent 1:0 classid 1:1 hfsc ls m2 100kbps ul m2 100kbps
tc class add dev eth0 parent 1:1 classid 1:10 hfsc rt m1 50kbps d 100 m2 10kbps
tc class add dev eth0 parent 1:1 classid 1:20 hfsc ls m2 70kbps
tc class add dev eth0 parent 1:1 classid 1:90 hfsc ls m2 10kbps
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 match ip src 192.168.10.0/24 flowid 1:10
tc filter add dev eth0 protocol ip parent 1:0 prio 1 u32 match ip src 192.168.20.0/24 flowid 1:20

[amuza]

I have also tested the examples at http://linux-tc-notes.sourceforge.net/tc/doc/sch_hfsc.txt in two different labs (both virtuals, I must say) and have not managed to see the expected latency results.